1. Field of the Invention
This invention relates to novel hot-water extracts of the neem bark. The hot-water extracts of the neem bark according to the invention possess activity against mouse L-5178Y cells and transplanted sarcoma 180 tumors and antimitotic activity in sea urchin eggs.
As a result of extensive studies on pharmacological actions of constituents contained in the neem materials, it has now been found that substances possessing activity as described above are produced by treating the neem bark prior to extraction with water at a temperature from 0.degree. to 40.degree. C. or, prior to such treatment, treating the same with a polar organic solvent having a dielectric constant from 15 to 35 and a non-polar organic solvent having a dielectric constant of 10 or lower and then subjecting the residue from the pretreatment to extraction with hot water, and that the pharmacological activities are enhanced by purifying the resulting extract by means of precipitation with an alcohol or by dialysis.
It is therefore the object of the present invention to provide hot-water extracts of the neem bark possessing activity against mouse L-5178Y cells and transplanted sarcoma 180 tumors.
2. Description of the Prior Art
It is heretofore known that neem extracts contain various pharmacologically active constituents. In fact, there is disclosed a method of producing cosmetics for the skin from the bark, leaves, flowers, fruits, branch, root epidermis or resin of neem by extracting the same with water of a hydrophilic solvent or by finely pulverizing the same (Japanese Patent Publication Nos. 28853/77, 28854/77 and 10125/78); a method of preparing from such neem materials the constituents possessing gastrointestinal and hepatic function-improving activities by extracting the same with a hydrophilic solvent and/or hot water (Japanese Patent Publication No. 10124/78); and a method of preparing from such neem materials the constituents that are effective for the therapy of dermatological and rheumatic diseases by extracting the same with a hydrophobic solvent (Japanese Patent Publication No. 13689/78). These prior-art methods are distinct from the present invention in that there are involved in order to produce the active constituents no pretreatment but direct extraction process only.